Methods and Systems for Making, Tracking and Authentication of Products

ABSTRACT

The invention foresees the labeling of each manufactured good with a digitally verified unique numeric identifier, and a central checking center allowing users to verify the authenticity of a particular cigarette pack or case by means of a cell phone interface. A system of secret key sharing allows secure authentication of each item and prevents code breaking or misuse.

FIELD OF THE INVENTION

This invention relates to the marking, tracking and authentication ofgoods, in particular, but not exclusively, of packaged goods, forexample packs or cartons of cigarettes and other tobacco products. Theinvention also relates to production control.

BACKGROUND TO THE INVENTION

Contraband and counterfeiting cause significant loss of revenue toproducers of traded goods as well as for national authorities. Moreover,the illegal sale of counterfeited goods of inferior quality isdetrimental to the customer and to the manufacturer.

Legally produced goods may also be illegally imported or traded, forexample in order to evade taxes or national regulations. It is thereforea major concern in several trade areas to detect and avoid unauthorizedparallel import channels.

The problems of contraband and counterfeiting are particularly acute forgoods subject to special taxation, like tobacco products. They alsoexist for many other kinds of traded products carrying a strong brandvalue, in particular for internationally traded products, such asperfumes, alcohols, watches and luxury goods in general.

It is a major concern of the manufacturers of such products to developmethods for reliably marking genuine products such as to enable theunequivocal identification of non-genuine products and the detection ofillegal imports.

It is common practice to identify traded goods by a production code, orserial number, impressed or printed on the package, for example acigarette pack or carton. Such a code, under certain conditions, enablesidentification of the production site, and the tracking of the tradechain for a particular item. Such knowledge is useful in identifyingsmuggled items.

A limitation of this practice is that the interpretation and validationof these production codes can be time-consuming and cumbersome. Forexample, authentication may require every production code impressed on amanufactured item to be recorded in a database and/or the transfer of alarge amount of confidential data from the manufacturing site to acentral database. These requirements may jeopardize reliability andsafety.

Another limitation of this practice is that the production codes caneasily be imitated or cloned. To partially obviate this limitation, itis known to add a covert taggant to the ink used to print the productioncode on the package. Counterfeit items carrying clones of valid codescan be thus detected by the absence of the covert taggant. The securityprovided by this method depends entirely on the ability to control thesources and the availability of the taggant.

The present invention aims to address the deficiencies in the prior artapproaches described above.

According to the invention, there is provided a method of markingmanufactured items, comprising: providing a plurality of secret codes toa checking centre and to a production line for the manufactured items;generating an ID code for each manufactured item; digitally signing eachID code by means of a secret derived from the plurality of secret codesand known to the checking centre; and marking each manufactured itemwith said signed ID code.

The present invention also provides a method of authenticating an itemmarked according to the method above comprising transmitting the saidsigned ID code to said checking centre; and authenticating the ID codeat the checking centre.

The invention also provides a system for marking manufactured itemscomprising: a generator, for generating collections of secret codes; aproduction line for manufacturing the items to be marked, the productionline comprising: a code generator for generating an ID code for eachmanufactured item; a digital Signor for signing the ID codes with asecret derived from the secret codes; a data transmitter fortransmitting the secret to a checking centre; and a marker for markingeach manufactured item with the signed ID code.

The invention also provides a method of authenticating a manufactureditem, comprising: generating a code and signing said code with a digitalsignature within a code generator; marking the item with the signedcode; transmitting the signed code to a checking centre over a publicnetwork; authenticating the digital signature by the checking centre;retrieving the significance of the code at the checking centre; andtransmitting the significance to a user over the public network.

A further aspect of the invention resides in a method of controlling thevolume of manufactured items marked the marking method above,comprising: gathering manufacturing volume information at the checkingcentre; and providing the manufacturing volume information to a user.

The invention also provides a method of tracking an item marked by tothe marking method above, comprising: transmitting the signed ID code tothe checking centre; authenticating the ID code by the checking centre;and retransmitting the tracking information related to the ID code to auser.

Embodiments of the various aspects of the invention have the advantagethat marking and authentication can be accessed and interrogatedremotely by an ordinary network, such as a land or mobile telephone. Themarking and authentication has the further advantage that it may not beviolated by counterfeiters. Moreover, the genuineness of a manufactureditem on sale can be checked easily, for example within a few seconds atthe point of sale.

Embodiments of aspects of the invention have the further advantage thatcloned codes and unauthorized code duplications may be identified, andthat the production volume, for example of a given manufacturer,manufacturing site or manufacturing line, may be controlled.

Embodiments of aspects of the invention have the further advantage thatthey may be used to replace the system of fiscal stickers that is usedin many countries to collect taxes, for example on tobacco products.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of exampleonly, and with reference to the accompanying drawings in which:

FIG. 1 is a schematic view of a marking and authentication systemembodying the invention;

FIG. 2 shows schematically a marking code format embodying theinvention;

FIG. 3 is a flow chart showing a code generation scheme embodying theinvention;

FIG. 4 is a flow chart showing a code authentication scheme embodyingthe invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the items to be marked are produced on one or moreproduction lines 101, 102. Each production line represents a productionfacility for one or more manufactured items. For example, a productionline may be a cigarette making and packaging line, with the manufactureditems being, for example, cigarette packs and cartons of at least onebrand. The production may be organized in batches, each batch beingdedicated to the production of a certain amount of identicalmanufactured items, for example cigarette packs and cartons of aparticular brand and type.

If there are two or more production lines, these lines may be physicallylocated at one manufacturing site 10, or at different production centres10 having various geographical locations.

Each production line comprises a code generator 106 arranged to generateand encrypt an identification code for each item manufactured on theproduction line 101. The production line 101 also comprises a marker107. Any suitable marking means may be used such as a continuous inkjetprinter, a drop-on-demand inkjet printer, a laser printer, or any otherprinter or marker that allows the marking of variable information, toimpress or print the identification code on each manufactured item.Depending on the nature of the packaging, the identification codes canbe impressed on each item, on an external package, on labels or in anyother convenient way. In one embodiment, the identification code isprinted on adhesive tags, or labels, to be applied to the manufactureditems, preferably non-removably.

In one embodiment the identification code is printed by a laser beam ona layer of laser-sensitive material deposited on the item or on theitem's package. This method allows the code to be impressed through atransparent wrapping layer.

Other possible supports for the identification code include holographicprinting, for example using the HoloSpot® format.

Embodiments of the invention may also include radio, electronic ormagnetic recording of the identification code, for example using an RFIDtransponder, EMID® tags or any other tagging means.

Preferably the system has means to count and report the number of codesgenerated and printed codes in each production batch or in a givenproduction period, as will now be described in detail. The productionlines 101 include a code generation system 106 which generates a uniqueencrypted identification code SUPI for each item produced. Preferably,the code generation system 106 is a fully autonomous computer ormicrocontroller dedicated to a particular production line 101.Preferably the code generation system 106 can communicate with achecking centre 30 via a secure internet connection 34, a local centralserver 15, or any other suitable data communication means.

The checking centre 30 receives and centralizes production data andprocesses queries from users 80, 70.

In one embodiment of the invention, several levels of packaging, such aspacks and cartons comprising several packs, which are manufactured onthe same manufacturing line 101, may be marked using common hardwareresources.

In one embodiment the code generation system 106 may comprise differentor shared software modules, loaded on a computer common to severalproduction lines, and serve several production lines at the same time.The code generation system 106 may be remotely located, for example inthe checking centre, and communicate the generated codes to theproduction lines, as required, by appropriate network means. The codegeneration system performs a number of functions, as described below,including the generation of ID codes for the items and the signing ofthose ID codes.

In the embodiment of FIG. 2, the unique identification code SUPI isobtained by processing data in a Production Information Code PIC. ThePIC combines various data related to the manufacture of the item, suchas a code MC identifying a manufacturing centre 10, a code PLidentifying a particular production line 101 within a manufacturingcentre 10, and codes YR, DY, HR identifying the year, day and hour,respectively, when a particular item was manufactured. In onealternative embodiment, the PIC may include a code generator ID insteadof the manufacturing centre and production line codes MC, PL.

To obtain the PIC, the individual data elements can be combined bydecimal or binary digit juxtaposition, by algebraic composition, byapplying a predefined shift value each data element and adding all theshifted values together, or by any other computational means. Preferablythe composition function is invertible, to allow decomposition of thePIC into the original elements MC, PL, YR, DY, I-IR. In the case of anon-reversible composition function, an additional element may beintroduced into the PIC to ensure uniqueness.

During each production hour, a production line fabricates a large numberof items 43. Each item 43 is identified, within a production hour, by anindividual number TI, for example a progressive number corresponding tothe chronological production sequence. Other manners of generating orassigning individual numbers are possible.

The production information code PIC and the individual number TI arecombined to provide an item identifier UPI. In the followingdescription, each UPI is unique to an item, for example to a singlecigarette pack or cigarette carton. However the invention is not limitedto this case, and includes variants with non-unique UPI numbers,distinguishable from each other by their different digital signatures.

The structure of the UPI code and the significance of the various fieldscomposing the UPI code are exemplary and are not limiting. Any codesuitable as item identifier code, having any arbitrary structure andsignificance, may be employed in the frame of the present invention.

A pseudorandom noise value code is combined with the UPI to authenticatethe code generator 106 that produces the code. The noise value acts as adigital signature for the code marked on each manufactured item producedby a particular manufacturing line 101 applied by the code generator 106which can be verified by the checking centre 30. To ensure verifiabilityby the checking centre, the pseudorandom noise code may obtained byencrypting a copy of the UPI code with a secret shared by the codegenerator and the checking centre. ‘Secret’ designates any data used forgeneration or authentication of a digital signature. Other ways ofadding a digital signature to the UPI code are possible, for example byusing asymmetric cryptography, and are included within the scope of theinvention. The secret is derived from secret codes, which may beregarded as static secret codes.

In one embodiment of FIG. 1, a centralized salt generator centre 20generates a large collection of secret codes, hereinafter designated asa ‘salt matrix’ containing a large number of precalculated random orpseudorandom data. Each salt matrix is preferably unique and istransmitted, in duplicate, to the intended manufacturing line 101 and tothe checking centre 30. Each manufacturing line 101 receives a uniquesalt matrix. The salt matrices transmitted to the checking centre arestored in a database 31 accessible to the checking centre 30 andpreferably included in the checking centre 30, with identification ofthe production lines 101, 102 to which they belong.

In the production lines, 101, 102, the salt matrices are used togenerate secret keys used to encrypt the UPI and to generate anelectronic signature, as it will be explained later.

To ensure authenticity, confidentiality and integrity of the saltmatrix, the matrix is preferably not transferred over a networkconnection, but rather recorded on non-volatile data carriers 50 such asCD-ROMs (Compact Disc Read-Only Memory), DVD-ROMs (Digital VersatileDisc Read-Only Memory), removable hard disks, magneto-optical devices orany suitable non-volatile memory device. The data carriers arephysically transferred to the checking centre 30 and to the productionlines 101, 102.

Preferably, to further increase safety, the salt matrices are encryptedand digitally signed by the salt generator 20, using a suitableencryption and authentication technique, such as DES (Digital EncryptionStandard), RSA (Rivest, Shamir, and Adelman algorithm), and the like.The salt matrices are not sent to the checking centre as part of thechecking process for items as will be discussed.

Preferably, a salt file contains the following components:

-   -   (i) A unique salt file identifier. (ii) The salt matrix        encrypted using a strong cipher, such as triple-DES, or AES        (Advanced Encryption Standard), according to a key generated in        the salt generator 20. A salt matrix may be, for example, a long        string of random or pseudorandom digits or characters.    -   (iii) The encrypted key needed to decode the salt matrix,        encrypted with a public-key cipher, for example RSA, using a        public key of the checking centre 30. This component is        requested in the salt file sent to the checking centre 30 and        may be omitted in the file destined to the production line 101.    -   (iv) A digital signature of the salt generator, obtained for        example by encoding a digest of the full message with a salt        generator private key, whose public counterpart is known to the        checking centre.

In this embodiment, the code generator of every production line 101 mustregister with the checking centre 30. This registration occurs onlywhenever a new salt matrix is used, or at prescribed intervals. Thesystem does not require constant communication between the codegenerators and the checking centre.

The registration procedure comprises the following steps:

-   -   (i) The code generator 106 of the production line 101 connects        to the checking centre 30 via a secure internet connection, or        via a local central server connected to the internet, and        initiates the registration by identifying itself.    -   (ii) A CD-ROM 50, containing a salt file, is loaded into the        code generator, its integrity is verified by its electronic        signature, and its unique identifier is transmitted to the        checking centre 30.    -   (iii) The checking centre retrieves its own copy of the salt        file, locally or remotely stored, by means of the unique        identifier.    -   (iv) If the salt file has been already used, the checking centre        stops the registration and requests another salt file, or        initiates appropriate action, for example issuing a warning to        the user or logging it in a security journal.    -   (v) If the salt file has not yet been used, and the        identification of the code generator is satisfactory, the        checking centre decrypts the secret key of the salt file with        its private key, and transmits it to the code generator over the        secure internet connection 34. In the case where the salt file        is not unique this step takes place regardless of whether or not        the salt file has already been used.    -   (vi) The code generator decrypts the salt matrix.

The registration procedure is arranged such that the salt matrix isnever transferred over the internet. Only a one-use decryption key istransmitted from the checking centre 30 to the code generator 106. Thesalt matrix is made available to the code generator only after a validregistration with the checking centre. This prevents unauthorized use ofthe code generator as no valid code can be generated.

Preferably the decrypted salt matrix is deleted when the code generatoris put out of service to prevent a malicious user from gaining access tothe salt matrix without proper registration. Additional means fordisabling the code generator and preventing unauthorized use of the codegenerator and the production line may be provided. The operation of thecode generator 106 will now be described with reference to FIG. 3.

At each production line 101, 102 at the beginning of each productionbatch, the code generator 106 generates a random salt index alpha, whichit transmits to the checking centre 30, with various information relatedto the item to be manufactured such as, for example, brand, intendedmarket of destination, packaging. A new salt index alpha is generated atevery change of production batch. Preferably the checking centreacknowledges successful receipt of the index alpha to the codegenerator. The index alpha may be regarded as a dynamic secret code.

In an embodiment the UPI code of the first item to be produced in thebatch is transmitted with the index alpha to the checking centre 30. Thesalt index alpha is stored in database 31 related to various informationabout the item to be manufactured. This enables the checking centre 30,upon receipt of a request to check a particular SUPI code, to retrievethe particular alpha and knowing the salt matrix used by the codegenerator 106 to sign that SUPI code, validate the signature.

The salt index alpha does not need to be communicated in real time tothe checking centre 30, at the beginning of each production batch. Oncea value of alpha has been chosen, the code generator can immediatelystart to generate valid codes and the value of alpha can be communicatedafter a delay of some hours, or more depending on the availability ofthe network connection.

Backup procedures such as telephone or fax may be used to communicatethe alpha to the checking centre, in case the network connection isunavailable. The random salt index alpha, the salt matrix and the UPIcode are used by the code generator for generating a noise code (step301) which is safe from cryptographic attacks. It does not allow thereconstruction of the original values of alpha, salts matrix and UPI. Avariety of known techniques are available for generating the noise codeincluding, but not limited to, table substitution, indexing, hashing,and variations thereof. The noise code so generated is unequivocallycalculated from the UPI, yet the inverse operation is computationallyimpossible.

The noise code is used as a digital signature, allowing validation ofthe UPI code. Preferably the alpha code and the salt matrix are combinedin a different way for each manufactured item, in order to render thedigital signatures robust against decryption attempts.

The salt matrix and the alpha code are known only by the code generatorand by the checking centre. Together they constitute a secret allowingthe code generator to generate signed codes which the checking centrecan subsequently verify.

The UPI number and the calculated noise code are combined at step 302and, preferably, the resulting code is obfuscated step 303, destroyingcorrelations between successive codes. The obfuscation operation isreversible, allowing the checking centre to retrieve the original UPIand noise value. Several known obfuscation techniques are possible. Theparticular obfuscation algorithm chosen is preferably not published.

The result of the obfuscation, is the unique SUPI code, which is printedon the manufactured items by the printer 107. Each of the items 43 ismarked with a unique digitally signed SUPI code, allowing identificationof the production batch in which it has been manufactured.

Preferably, data relating to the production batch, e.g. product type,brand, intended market of destination, packaging is stored in thedatabase 31 with the index alpha at the start of the batch. This data isaccessible to the checking centre. The SUPI code can be printed on themanufactured item by a variety of printing and marking techniques, forexample continuous inkjet printing, drop-on-demand printing, laser, etc.The SUPI code may be printed in a human readable format, or amachine-readable formats such as 1-D or 2-D barcodes or characterssuitable for OCR (Optical Character Recognition).

Preferably the SUPI code is printed or recorded by a printing orrecording means comprising a device such as a code counter or aregister, for counting the exact number of marked items, either during aproduction batch or in a given time interval. The exact number of markeditems may be stored in the database 31 accessible to the checking centreand used for production volume control.

In one preferred embodiment, the SUPI code is printed with an inkcontaining a covert taggant, to allow a quick validity check withoutquerying the checking centre.

The production line 101 may have a sensor to detect the presence of theSUPI (either using a vision system and/or by detecting the coverttaggant, if applicable). The sensor can be connected to the controllerof the production line, thus enabling the rejection of items notproperly marked. The controller can be set to prevent the productionline from operating if the sensor unit is disconnected, faulty or onrejection of a defined number of items. A history of rejections may belogged in the Code Generator and communicated to the Checker formonitoring purposes by authorized users. The production information code(PIC code) may be repeated on the manufactured item, in plain formatwithout encryption or obfuscation, allowing the user to verify theanswer provided by the checking centre 30 and useful for management andmonitoring of the supply chain.

After leaving the production centre 10, the manufactured items 43 aredistributed and commercialized in the usual way. At each stage of thedistribution and commercialization process, the authenticity of the itemcan be verified by sending a query containing the SUPI code of thepackage to the checking centre. Such verification may be requested forexample by generic users, such as retailers, consumers, or customsagents, and by privileged users, for example employees of themanufacturers, or organizations having a privileged agreement with themanufacturer. The SUPI codes may also be employed for tracking themanufacturing items along the distribution and commercialization chain.

FIG. 4 shows the processing of a request to validate a SUPI code in thechecking centre. The received SUPI code is first de-obfuscated at step402, by applying the inverse of the obfuscation function describedabove. At step 402 the original UPI and noise component are extracted.The checking centre performs a first level authentication at step 404 onthe manufacturing centre MC and the production line PL. If PL is foundto correspond to an existing production line of manufacturing centre MC,the authentication proceeds to the next level, otherwise a response isgenerated at 420 that the SUPI code is invalid, and the item iscounterfeit. In the second level of authentication, the checking centre30 uses the secret salt matrix received by the salt generator 20 and thealpha code transmitted at the beginning of a production batch. At 410the checking centre retrieves the information related to the productionbatch corresponding to the received UPI code from the database 31. Ifthe retrieval is successful, the retrieved salt matrix and the alphacode are used at 411 to reconstruct the noise code from the received UPIcode and to verify the validity of the signature. If the received noiseand the reconstructed noise do not match, or if no data corresponding tothe PIC is present in the database, the SUPI code is identified asinvalid and the checking centre responds at 420 that the item iscounterfeit.

In a third level of authentication at step 412, the checking centreverifies whether queries for the same SUPI code have been submitted morethan a predefined number of times. In this case, there is then asuspicion that the SUPI code may be a clone of a valid code, identicallyprinted on a large number of counterfeits. The checking centre thenissues a reply at step 430 specifying, that the submitted code is valid,but the item is likely to be counterfeit.

The discovery of cloned codes can be refined by making use of otherinformation, for example the origin of the query, which can bedetermined if the query originated from a phone, or the elapsed timebetween queries.

Here, ‘cloning’ means multiple copying of a valid production code, forexample for tagging counterfeited articles. If the code has been foundvalid (step 440), the checking centre retrieves the significance of thecode and transmits it to the user, preferably in natural language, forexample: “your code corresponds to a pack of brand XYZ, intended marketof retail Switzerland”, or another appropriate formulation.

The information returned by the checking centre may allow the trackingof the production information for each item, for example informationabout the production unit, the production line, the date and time ofproduction. Such information can be returned in encoded form, or innatural language.

Optionally the checking centre can formulate the significance of thecodes into several languages, and choose the most appropriate languagefor the reply, according to the origin or language of the query. In apreferred embodiment, the public interface to the checking centreincludes a SMS (Short Message Service) or USSD (UnstructuredSupplementary Services Data) portal 60 of a public radio communicationnetwork, for example a telephone network supporting text or numericmessages like GSM, TDMA, CDMA, PDC, or UMTS standard networks, throughwhich the users 80 can send queries to the checking centre 30 in form oftext messages, or SMS, from their own cell phone 82, and receive thereply from the checking centre in the same way or by another channel,for example by a voice call. In this way the user 80 can verify an item43 directly at the point of sale 77.

The communication may alternatively or additionally be over the internet32 by a web server at the checking centre 30, by an email server or aWAP (Wireless Application Protocol) server.

Alternatively or additionally, the communication may be to a telephonevoice server, able to interpret voice commands or DTMF (Dual-ToneMulti-Frequency) signals generated by a telephone keyboard.

Embodiments of the present invention allow a generic unidentified userto authenticate a manufactured item over a public network, such as theinternet 32, a telephone network or a mobile telephone network. The userneed not identify himself, nor has he to have access to any secret codeor sensitive information. However, each item can be identified in acryptographically safe way.

In a preferred embodiment, a privileged user 70, for example an employeeof the manufacturer, may have a preferred access to the checking centre30 and retrieve additional privileged information, unavailable togeneric users, for example production volume information, or statisticalinformation on the access to the checking centre. In this case, aprivileged user may query information on a particular SUPI withoutmarking it as cloned for successive queries from ordinary customers 80.

The privileged user may communicate with the checking centre 30 by apublic network, or an intranet connection 33.

In a further embodiment the checking centre may provide, to generic orprivileged users, additional information to which it has access, whichare not contained in the UPI code, for example expiry date, warrantyinformation, address of local support, or previous trade steps,importation routes and so forth.

Additionally the checking centre may gather and store information onproduction volumes, for example the number of items produced in eachproduction batch by each production line, as well as statisticalproduction data per brand and per intended market. Such productionvolume information may be used for production management, or forofficial purpose, and may be available to selected users.

Identification steps may be provided to identifying known privilegedusers, for example by passwords, cookies, voice or biometric data, or byany suitable identification means. The checker may include, or haveaccess to, a user rights database for storing the profiles of varioususers, and determining to which information each user has access.

It will be appreciated that embodiments of the present invention do notrequire a permanent connection between the manufacturing lines and thechecking centre, nor that all the SUPIs be individually stored in adatabase. In fact, no identification code is stored. The digitalsignature ensures that each item can be verified with a minimal transferof confidential data, providing a high level of reliability and safety.Moreover production volume can be exactly accounted for. As noidentification code is stored at the checking centre, the databaserequired by the checking centre is relatively small compared to thatwhich would be needed if the codes were stored.

In some situations, particularly if the manufactured goods are subjectto special tax regulations, official government bodies may submitrequests to the checking centre to obtain the appropriate productiondata, for example production volumes. In such cases, the checking centre30 may be maintained by a trusted third party independent from theproducer of the manufactured items 43. The embodiments described may beused to replace the system of fiscal stickers that is used in manycountries to collect taxes, for example on tobacco products.

1. A method of marking manufactured items, comprising: providing aplurality of secret codes to a checking centre and to a production linefor the manufactured items; generating an ID code for each manufactureditem; digitally signing each ID code by means of a secret derived fromthe plurality of secret codes and known to the checking centre; andmarking each manufactured item with said signed ID code.
 2. A method ofclaim 1, comprising using a covert taggant or a laser device in themarking step.
 3. A method according to claim 1, wherein said pluralityof secret codes are precalculated random codes.
 4. A method according toclaim 1, providing the plurality of secret codes includes physicaltransfer of a non-volatile data support, on which the secret codes arerecorded.
 5. A method according to claim 1, wherein said secret derivedfrom said plurality of secret codes is derived at each of a plurality ofproduction lines.
 6. A method according to claim 1, wherein part of saidsecret is transmitted by a code generator to the checking centre via asecure network connection.
 7. A method according to claim 1, wherein theplurality of secret codes is a collection of random codes, andcomprising: generating an index relating to the manufacture of one ormore items; transmitting the index to the checking centre; deriving thesecret by a code generator, from the collection of random codes and fromthe index; and digitally signing each ID code for each manufactured itemwith a noise code derived by encrypting a copy of the ID code with thesecret.
 8. A method according to claim 7, wherein the secret is furtherderived from the ID code.
 9. A method according to claim 1, comprisingtransmitting additional information concerning the manufactured items tothe checking centre.
 10. A method according to claim 1, wherein saidchecking centre is managed by a trusted third party, independent fromthe manufacturer of the manufactured item.
 11. A method according toclaim 1, wherein said marking is performed on packaging of saidmanufacturing article.
 12. A method according to claim 1, wherein the IDcode comprises at least one of: a production site identifier; aproduction line identifier; a code generator identifier; a productidentifier; and time information.
 13. A method according to claim 1,comprising encrypting the ID code.
 14. A method according to claim 1,wherein said item is a cigarette pack or a cigarette carton.
 15. Amanufactured item marked by the method according to claim
 1. 16. Amethod of authenticating an item marked according to the method of claim1 comprising: transmitting the signed ID code to the checking centre;and authenticating the signed ID code at the checking centre.
 17. Amethod according to claim 1, comprising: marking on each manufactureditem part of the information contained in the ID code for that item; andverifying the consistency of information with processed informationretransmitted by the checking centre.
 18. A method according to claim16, comprising retransmitting additional information related to thetransmitted ID code by the checking centre.
 19. A method according toclaim 16, comprising detecting cloned 40 codes at the checking centre.20. A checking centre for authenticating an item by the method of claim16.
 21. A system for marking manufactured items comprising a generatorfor generating collections of secret codes; a production line formanufacturing the items to be marked, the production line comprising: acode generator for generating an ID code for each manufactured item; adigital signor, for signing the ID codes with a secret derived from thesecret codes; a data transmitter, for transmitting the secret to achecking centre; and a marker for marking each manufactured item withthe signed ID code.
 22. A system according to claim 21, wherein saidmarker comprises a printer or a laser device.
 23. A system according toclaim 21, wherein the production line is arranged for the production oftobacco products.
 24. A system according to claim 21, wherein thegenerator comprises a data recorder, for recording the collection ofsecret codes on a non-volatile data support.
 25. A system according toclaim 21, wherein the checking centre comprises an interface foraccepting text or numeric queries from a network and for transmittinganswers via the network.
 26. A system according to claim 21, wherein thegenerator for generating collections of secret codes is a saltgenerator.
 27. A system according to claim 21, wherein the productionline comprises a sensor to detect the marked signed ID code.
 28. Amethod of authenticating a manufactured item, comprising: generating acode and signing said code with a digital signature within a codegenerator; marking the item with the signed code; transmitting thesigned code to a checking centre over a public network forauthentication; authenticating the digital signature by the checkingcentre; retrieving the significance of the code at the checking centre;and transmitting the significance to a user over the public network. 29.A method according to claim 28, wherein codes generated by the codegenerator are not stored.
 30. A method according to claim 28, whereinthe code is signed with a secret shared by the code generator and thechecking centre.
 31. A method according to claim 30, wherein the secretis extracted from a collection of secret codes shared by the codegenerator and the checking centre and is modified during operation ofthe code generator.
 32. A method according to claim 30, wherein saidsecret is different for each manufactured item.
 33. A method ofcontrolling the volume of manufactured items marked according to themethod of claim 1, comprising: gathering manufacturing volumeinformation at the checking centre; and providing the manufacturingvolume information to a user.
 34. A method according to claim 33,wherein the manufacturing volume information is obtained from ID codestransmitted to the checking centre.
 35. A method of tracking an itemmarked according to the method of claim 1 comprising: transmitting thesigned ID code to the checking centre; authenticating the signed ID codeby the checking centre; and retransmitting the tracking informationrelated to the ID code to a user.
 36. A method according to claim 34,wherein the tracking information is obtained from the ID codes ofmanufactured items transmitted to the checking centre.
 37. A methodaccording to claim 32, comprising identifying the user.
 38. A methodaccording to claim 33, comprising a step of denying information to usersnot belonging to a predefined group of privileged users.
 39. A method ofauthenticating manufactured items, comprising marking the items by:providing a plurality of secret codes to a checking centre and to aproduction line for the manufactured items; generating an ID code foreach manufactured item; digitally signing each ID code by means of asecret derived from the plurality of secret codes and known to thechecking centre; and marking each manufactured item with said signed IDcode; and authenticating a manufactured item on request by validatingthe secret at the checking centre.
 40. A system for authenticatingmanufactured items, comprising: a system for marking manufactured itemscomprising: a generator for generating collections of secret codes; aproduction line for manufacturing the items to be marked, the productionline comprising: a code generator for generating an ID code for eachmanufactured item; a digital signor, for signing the ID codes with asecret derived from the secret codes; a data transmitter, fortransmitting the secret to a checking centre; and a marker for markingeach manufactured item with the signed ID code; the authenticationsystem further comprising a checking centre for authenticating amanufactured item on request by validating the secret.